In separate talks with U.S. Defense Secretary Jim Mattis and Deputy Secretary of State John Sullivan, Kono underscored that the two countries stand shoulder-to-shoulder in pushing for a complete, verifiable and irreversible denuclearization of the Korean Peninsula, according to a Japanese official.
The two sides affirmed that Tokyo and Washington will maintain "maximum pressure" on Pyongyang until it takes concrete measures to rid itself of nuclear weapons, the official said.
Kono, who arrived in Washington on Thursday for a three-day visit, seeking the United States' cooperation in resolving North Korea's abduction of Japanese nationals in the 1970s and 1980s.
His trip comes as U.S. President Donald Trump agreed last week to meet with North Korean leader Kim Jong Un by the end of May in an effort to achieve "permanent denuclearization" of the peninsula.
The first-ever U.S.-North Korea summit would follow an inter-Korean summit slated for late April at the truce village of Panmunjeom.
In early April, Japanese Prime Minister Shinzo Abe plans to visit Washington to ensure close coordination with Trump in addressing North Korea's nuclear and missile programs, as well as the abduction issue, a priority issue for Abe.
The time and location of the Trump-Kim summit have yet to be determined, although neutral countries such as Sweden and Switzerland have been floated as possible hosts.
The United States and North Korea have not signed a peace treaty concluding the 1950-53 Korean War.
Signs of diplomatic opening have raised hopes for a breakthrough on the North Korean nuclear issue.
Kim is reportedly committed to denuclearization, but doubts persist as to whether he is serious about giving up the North's nuclear weapons.
Initially, Kono had planned to meet with U.S. Secretary of State Rex Tillerson. But given Trump's dismissal of Tillerson on Tuesday, Kono will hold talks with Sullivan, who is serving as acting secretary.
On Saturday, the Japanese foreign minister will meet with his South Korean counterpart Kang Kyung Wha in Washington to exchange views on the planned summit between South Korean President Moon Jae In and Kim.
Kang is on a three-day visit to the U.S. capital through Saturday, as well.
On Thursday, Kono met with U.S. Trade Representative Robert Lighthizer and requested that Japan be exempted from Trump's controversial decision to impose stiff tariffs on steel and aluminum imports.
